Progressive Development of Pseudomyxoma Peritonel After Resection of Low-Grade Mucinous Adenocarcinoma of the Appendix

Abstract

Introduction: Pseudomyxoma peritonei (PMP) is a rare condition, commonly originating from the appendiceal tumors. We present a case of progressive PMP after surgery for low grade mucinous adenocarcinoma of the appendix. Case Report: A 58-year-old female with history of total abdominal hysterectomy and bilateral salpingo-oophorectomy (TAH-BSO) for fibroids and appendectomy 10 years ago remained asymptomatic until she presented with abdominal pain and weight loss 2 years ago. Review of surgical history revealed that appendectomy was also done while TAH-BSO was being performed because of abnormal-appearing appendix with mucin. Biopsy showed low-grade mucinous adenocarcinoma. EGD and colonoscopy did not reveal any acute pathology. CT abdomen revealed extensive peritoneal cystic masses with scalloping of the liver, spleen, and mesentery, consistent with PMP. She underwent cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Biopsies revealed low-grade mucinous adenocarcinoma with nonsignificant right colon and distal ileum. She was started on systemic chemotherapy for progressive disease on follow-up CT imagings. Progression of disease continued on repeat imagings after 3 months of chemotherapy, but the patient had no symptoms. CEA and CA 19-9 remained elevated. The patient is being monitored and further CRS with HIPEC will be planned if she develops more progressive disease with symptoms. Discussion: Appendiceal tumors are most commonly found incidentally when obtained for unrelated condition. A large National Cancer Institute series has shown the most frequent histology as mucinous adenocarcinoma with carcinoid tumors in only 11%. PMP commonly originates from benign tumors of appendix and characterized by diffuse intraabdominal collections of gelatinous material with mucinous implants on the peritoneal surfaces. It has also been described to arise from adenocarcinomas of the appendix and other intra-abdominal organs as well as breast, ovary, and fallopian tubes. The most common symptoms are abdominal distension and pain. Scalloping of the liver, spleen, and mesentery, as well as calcifications on CT imaging are typical. Tumor markers (e.g. CEA, CA 19-9, CA 125) correlate with prognosis and recurrence rates. Optimal treatment with CRS and HIPEC have been reported to improve 5-year survival as 62.5-100% for low-grade and 0-65 % for high-grade disease. Conclusion: PMP can be progressive after many years of surgical resection of the primary tumor, as in our case. Optimal treatment such as CRS and HIPEC have been shown to improve survival. Periodic close follow-up visit with tumor marker and CT abdomen are important to assess the progression of disease, which can determine the further management.